1. Field of the Invention
The invention relates generally to the providing of pasty or liquid- to cream-like substances.
2. Background Information
Dispensers for providing washing and skin care lotions, creams, and similar substances are often used in the fields of hygiene and cosmetics. Such dispensers have a container, in which a relatively large amount of the substance is stored. Dispensing of a small amount of the substance takes place through a delivery opening, which is connected with a pump mechanism, for example. In simpler versions of such dispensers the substance is dispensed through the delivery opening by compressing the container.
Dispensers are also known where the delivery opening is closed by means of a rotatably seated spherical closure element, for example. In their operating position, such dispensers are seated with the delivery opening pointing down. Here, the size and fitting of the spherical element in the delivery opening is selected in such a way that the substance cannot run out unintentionally. Operation of the dispenser takes place by touching the closure element, wherein a section of the surface of the closure element, which is moistened by the substance, comes into contact with the hand of the user, or a cloth, a sheet of paper or the like, by being rotated. A small amount of the pasty or liquid- to cream-like substances placed into the container can be dispensed in this manner.
The known dispensers for pasty or liquid- to cream-like substances mostly have a relatively complicated, and therefore expensive structure. Spherical closure elements must be manufactured extremely accurately and fitted, so that sealing is assured. When being touched, for example by a hand or by a flat article, there mostly is only an essentially linear contact. In fact, the spherical closure element could be replaced by one or several roller-shaped elements for achieving a more extensive contact. However, roller-shaped closure elements generally pose larger sealing problems than spherical ones and therefore must be fitted particularly exactly into holders in the delivery opening. The amount of substance which can be dispensed also depends to a large degree on the ability of the surface of the closure element to become wet. Therefore the latter must be manufactured particularly exactly, and damage to its surface must be prevented as much as possible. Often the closure element cannot be simply rotated, because of which the dispensing of the pasty or liquid- to cream-like substances is hampered. Simple dispensers, where the substance is dispensed by compressing the container, are very inexact regarding the amount of substance being dispensed, and are impractical for wetting articles with more extensive areas, such as a sheet of paper or a cloth.
It is the object of the present invention to overcome these disadvantages of the dispensers for pasty or liquid- to cream-like substances of the prior art. A dispenser in accordance with the species is to be simplified in regard to its construction. In connection with this, the dependability of the seal in the operating position is to be assured, and the dispensed amount of the pasty or liquid- to cream-like substances is to be controllable in a relatively simple way.
The attainment of these objects consists of an apparatus and a method for providing pasty or liquid- to cream-like substances having the apparatus or method characteristics recited in the characterizing portions of the respective independent patent claims of the respective categories. Advantageous embodiment variations and/or further developments of the invention are the subject of the dependent apparatus or method claims, as well as of the use claims.
An apparatus for providing a pasty or liquid- to cream-like substance comprises a container, in which a relatively large supply of the substance is stored, and a closure and dispensing element, which closes a delivery opening of the container. On the one hand, the closure and dispensing element is used for keeping back the substance stored in the container, and on the other hand for dispensing a small amount of this substance when the closure and dispensing element comes into contact with a surface to be wetted. In accordance with the invention, the closure and dispensing element is designed to be planar and is provided with openings arranged in a grid-like manner. On the one hand, the openings are designed in such a way that in the position of use of the apparatus they keep back a pasty or liquid- to cream-like substance arranged inside the container against the pressure exerted by the substance, and on the other hand dispense a small amount of the pasty or liquid- to cream-like substance in a controlled manner when the outside of the closure and dispensing element touches a surface to be wetted.
The provision of a closure and dispensing element, which is designed to be planar and has openings arranged in a grid-like manner noticeably simplifies the construction of the apparatus in accordance with the invention. In place of spherical or possibly roller-shaped closure elements which, for reasons of tightness, must be manufactured highly precisely and fitted into receivers in the delivery opening, a simple screen structure is used. The openings in the closure and dispensing element, which is designed to be planar, are dimensioned in such a way that the retention capability is sufficient to hold back the pasty or liquid- to cream-like substance arranged inside the container against the exerted pressure. The substance cannot leave through the openings in an uncontrolled manner. Instead, as a result of the dimensions of the openings there is only a formation of drops, wherein the drops protrude over the outer surface of the closure and dispensing surface. The substance is dispensed only upon contact with a surface to be wetted, for example the surface of a sheet of paper, or a fabric or a hand. Because of the size of the openings, this does not take place arbitrarily, but controlled, preferably by drops. When dispensing the pasty or liquid- to cream-like substance, the closure and dispensing element designed in accordance with the invention is at rest in respect to the delivery opening. Therefore the simple design of the apparatus in accordance with the invention avoids sealing problems caused by rotatably seated closure elements. The apparatus in accordance with the invention can also be produced more simply and cost-effectively because of the simplified construction.
The closure and dispensing element, which is designed to be planar, can be embodied to be convex or concave. However, it can be particularly simply produced as a flat screen plate. For example, it can be made as a small flat plate of metal or plastic.
In an advantageous embodiment variation of the invention, the openings are designed to be funnel-shaped. To this end, they have a clear cross section at the outer surface of the closure and dispensing element, which is smaller than in an area closer to the container interior. Because of this, the opening can be designed in a way which hampers the flow of the substance as little as possible. The drop formation then only takes place in the area of the openings with the smallest cross section. By means of the cross section of the openings, which tapers toward the outer surface, it is also assured that the formed drops protrude sufficiently far beyond the outer surface of the closure and dispensing element, which is designed to be planar, and are stripped off upon contact with the surface to be wetted.
The dimensioning of the opening must take into consideration the conditions of compatibility set by the liquid to be provided, so that the two goals, the retention capability of the screen structure on the one hand, and the controlled dispensing onto a surface which is in contact with the outer surface of the screen structure, for example a sheet of paper, a web of fabric or the hand, can be achieved on the other hand. Essential factors which are of importance here are the surface tension xcex1(T) and the density xcfx81(T) of the pasty or liquid- to cream-like substance, the height h of the substance inside the container, the respective temperature T of the substance, the pressure p1 in the container, or the atmospheric pressure po, and the acceleration due to gravity g.
The openings can have an elongated, round, or also a regular polygonal clear cross section. The smaller dimension of the clear cross section of the openings at the outer surface of the closure and dispensing element is particularly decisive for the drop formation. Taking into consideration the previously mentioned conditions of compatibility, its is advantageously selected in accordance with the equation:
dxe2x89xa64xcex1(T)/[h*xcfx81(T)*g+p1xe2x88x92po]. 
Because the closure and dispensing element, which is designed to be planar, has a thickness which is less than one-half of the smaller dimension of the clear cross section of the openings on its outer surface, it is assured that the drops formed at the openings protrude sufficiently far past the outer surface of the closure and dispensing surface, so that they can be dispensed in a controlled manner when in contact with a surface to be wetted.
Particularly good relations between the retention capability on the one hand, and the ease of dispensing on the other when the outer surface is in contact with a surface to be wetted, can be achieved with a closure and dispensing element, which is designed to be planar and has a honeycomb-like structure, where each opening at the outer surface has the contours of a preferably regular hexagon.
In a variation of the invention the container is embodied to be closed, except for the delivery opening, in order to prevent miscellaneous contamination of the pasty or liquid- to cream-like substance stored in the container.
In order to be able to use the apparatus again after it has been completely emptied, the closure and dispensing element, which is designed to be planar, is provided on a cover element, which can be removably placed on a collar surrounding the outlet opening of the container. Embodied in this way, the container can be used again after the cover element has been removed.
It can also be advantageous to hold the closure and dispensing element exchangeably in the cover element. This offers the option of employing the closure and dispensing elements in connection with specific substances. The production of the cover element takes place completely separately from the production of the closure and dispensing elements. The two elements are only joined in a final assembly process, which can already take place with regard to the substance to be stored in the container. The cover element and the closure and dispensing element can be made of different materials. For example, the cover element can be a plastic part, and the closure and dispensing element a metal part.
It is usually also advantageous if the areas of the outer surface of the closure and dispensing element remaining between the openings have a hydrophobic surface. By means of this step it is assured that the drop formation takes place only at the openings, and no running of the formed drops occurs.
In a further development of the invention that closure and dispensing element can have two screen plates, which are preferably designed to be planar. The two screen plates are arranged rotatable in respect to each other so that the clear cross section of the openings is changed. This offers a simple opportunity to adapt the clear cross section of the openings to the conditions of compatibility set by the pasty or liquid- to cream-like substance to be provided. One of the two screen plates is then arranged fixed in place in respect to the delivery opening. The second screen plate, which is rotatable relative to the first one, can also, for example, be used as a separate closure element in order to compartmentalize the contents of the container if required, or to provide a drip protection. The relative rotation of the two screen plates in respect to each other can take place manually or also automatically in further embodiment variations of the invention.
The method in accordance with the invention for providing a pasty or liquid- to cream-like substance, which is stored in a container and can be applied to a surface by contact of the surface to be wetted with a closure and dispensing element which closes the delivery opening of the container, is distinguished in that, in the position of use of the container, the pasty or liquid- to cream-like substance is located above a closure and dispensing element, which is embodied to be planar, preferably plate-shaped, and is provided with openings arranged in a manner of a grid. The opening are designed in such a way that they hold back the pasty or liquid- to cream-like substance against the pressure exerted by the substance and release a small amount of the substance to the surface in a controlled manner only when there is contact between the surface to be wetted and the outer surface of the closure and dispensing element. Because of the planar design of the closure and dispensing element, contact with the surface to be wetted is also planar and not only along lines, such as is the case with spherical closure elements. Because of this a relatively large amount of the substance to be provided is dispensed to the surface of, for example, a sheet of paper, a textile web or a hand. Dispensing essentially takes place at a controlled rate of dispensing, since only the droplets which protrude from the openings are brushed off upon contact.
Dispensing the pasty or liquid- to cream-like substance in this case is usefully performed by a lateral relative movement between the outer surface of the planar closure and dispensing element and the surface to be wetted.
For filling the container, the planar closure and dispensing element is removed from the delivery opening and the substance is poured through the delivery opening into the container. Because of this method it is possible to produce the container with only one opening, the delivery opening. Additional fill openings with covers and the like can be omitted, which has an advantageous effect on the manufacturing process and the manufacturing costs.
In a variation of the invention, wherein the closure and dispensing element is constituted by two screen plates, the two screen plates are rotated in respect to each other for adapting the opening cross section of the opening to the pasty ro liquid- to cream- like substance to be provided.
The claimed invention is particularly distinguished by the use of a planar screen structure as the closure and dispensing element for the delivery opening of a container for holding back a pasty or liquid- to cream-like substance, and for the controlled dispensing of the substance when contacting an outer surface of the screen structure with a surface to be wetted.
In this case the dimensioning of the openings is provided in such a way, that its smaller size is in accordance with the equation:
dxe2x89xa64xcex1(T)/[h*xcfx81(T)*g+p1xe2x88x92po], 
wherein xcex1(T) identifies the surface tension and xcfx81(T) the density of the pasty or liquid- to cream-like substance, h stands for the height of the substance inside the container, T identifies the respective temperature of the substance, p1 or po identify the pressure in the container, or the atmospheric pressure, and g stands for the acceleration due to gravity.
The fields of hygiene and/or cosmetics are to be mentioned as applications for an apparatus equipped in accordance with the invention for dispensing pasty or liquid- to cream-like substances to a flat substrate, for example a piece of paper or a textile web, or also directly to a hand. Planar coating, impregnating and adhesive applications are also considered to be areas of use of the apparatus in accordance with the invention. In case of substances which harden by contact with the air it is possible to take precautions on the apparatus for isolating the adhesive from the ambient air during storage. For example, an additional cover can be provided, which is placed over the closure and dispensing element.